XChaCha20 (JavaScript)

This is a pure JavaScript implementation of XChaCha20 (and therefore ChaCha20 and HChaCha20), for use in polyfill libraries.

Important Security Warning

This library provides unauthenticated encryption. You shouldn't use it directly. It's meant to be a building block for other, high-level protocols.

Use sodium-native instead!

Installing this Library

npm install xchacha20-js

Using this Library

Usage is straightforward.

const XChaCha20 = require('xchacha20-js');

let xcha20 = new XChaCha20;
let message = "test message";
let key = Buffer.from('808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9f', 'hex');
let nonce = Buffer.from('404142434445464748494a4b4c4d4e4f5051525354555658', 'hex');

let blockCounter = 1; // Optional, defaults to 1 per the RFC
xcha20.encrypt(message, nonce, key, blockCounter).then(
    function (ciphertext) {
        xcha20.decrypt(ciphertext, nonce, key, blockCounter).then(
            function (plaintext) {
                console.log(plaintext.toString() === message); // true
            }
        )
    }
);

Alternatively. using async / await...

const XChaCha20 = require('xchacha20-js');

let xcha20 = new XChaCha20;
let message = "test message";
let key = Buffer.from('808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9f', 'hex');
let nonce = Buffer.from('404142434445464748494a4b4c4d4e4f5051525354555658', 'hex');

(async function(){
    let blockCounter = 1; // Optional, defaults to 1 per the RFC
    let ciphertext = await xcha20.encrypt(message, nonce, key, blockCounter);
    let plaintext = await xcha20.decrypt(ciphertext, nonce, key, blockCounter);
    console.log(plaintext.toString() === message); // true
})();